American Board of Ophthalmology (ABO) Practice Exam 2025 – The Complete All-in-One Guide to Exam Success

The presence of a "halo" effect around lights is primarily associated with conditions that affect the clarity of the lens of the eye, leading to optical aberrations. Cataracts, a clouding of the lens, often result in the scattering of light as it passes through the affected lens, producing halos around lights, especially in low-light conditions or at night. This scattering effect is due to the irregularities or opacities within the cataractous lens.

Glaucoma, particularly angle-closure glaucoma, can also cause a halo effect around lights. In this condition, increased intraocular pressure can lead to corneal edema, which similarly scatters light entering the eye.

The other conditions listed do not primarily produce a halo effect. For example, retinal detachment or age-related macular degeneration (AMD) may lead to more significant vision loss or distortion of central vision but are not typically characterized by halos. Likewise, diabetic retinopathy and myopia can cause vision impairments but do not create halos around lights. Night blindness and color blindness primarily alter the ability to perceive light and color rather than causing optical distortions in the presence of light sources.

Thus, cataracts and glaucoma are the conditions most commonly associated with a halo effect, making the